Messages in this thread | | | Date | Thu, 1 Jun 2023 09:50:41 +0200 | From | Miquel Raynal <> | Subject | Re: [RFC PATCH v5 0/6] refactoring, fixes and updates for Meson NAND |
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Hi Arseniy,
AVKrasnov@sberdevices.ru wrote on Thu, 1 Jun 2023 09:18:43 +0300:
> Hello, > > this patchset does several things:
All the fixes should contain:
Fixes: <hash> ("log") Cc: stable@vger.kernel.org
> > 1) Fixes value of ready/busy command. This new value was suggested by > Liang Yang <liang.yang@amlogic.com>. > > 2) Adds waiting for command completion by calling 'nand_soft_waitrdy()' > instead of using ready/busy pin and command from 1). This is really > needed because I don't have device with such pin implemented. > > 3) It moves OOB free bytes to non-protected by ECC area. Here are some > details: > > Current OOB free bytes are 4 bytes (2 x 2 user bytes) under ECC engine. > Here is how it looks like in the current implementation: > > [ 2B user bytes ][ 14B ECC codes ] > [ 2B user bytes ][ 14B ECC codes ] > [ 16B unused area, not protected by ECC ] > [ 16B unused area, not protected by ECC ] > > All 4 user bytes are protected by ECC. This patch changes OOB free > bytes in this way: > > [ 2B unused area ][ 14B ECC codes ] > [ 2B unused area ][ 14B ECC codes ] > [ 16B user bytes, not protected by ECC ] > [ 16B user bytes, not protected by ECC ] > > Now OOB user bytes are 32 bytes instead of 4 bytes and not protected > by ECC. > > Motivation of this layout comes from problem with JFFS2. It uses OOB > free bytes for cleanmarkers. Each cleanmarker is 4 bytes and written > by JFFS2 driver (small remark - cleanmarkers are always written in > case of NAND storage for JFFS2). > We have two ways to write this data to OOB (e.g. user bytes): > > 1) ECC mode. In this case it will be ECC covered user bytes, e.g. > writing this bytes will update ECC codes. Problem fires, when > JFFS2 tries to write this page later - this write makes controller > to update ECC codes again, but it is impossible to do it correctly, > because we can't update bits from 0 to 1 (only from 1 to 0). > > 2) Raw mode. In this case ECC codes won't be updated. But later, it > will be impossible to read this page in ECC mode, because we have > some user bytes, but ECC codes are missed. > > So let's move OOB free bytes out of ECC area. In this case we can > read/write OOB separately in raw mode and at the same time work with > data in ECC mode. JFFS2 is happy now. User bytes are untouched - all > of them are ignored during non-OOB access. > > I've tested this with mount/unmount/read/write cases for JFFS2 and > nanddump/nandwrite utlities on AXG family (A113X SoC). > > Here is link to discussion: > https://lore.kernel.org/linux-mtd/a9f8307a-77d7-a69f-ce11-2629909172d2@sberdevices.ru/T/#m3087bd06386a7f430cd5e343e22b25d724d3e2d7 > > 4) Replaces calculation of OOB related thing with macros. This is just > cosmetic change. > > 5) Checks buffer length on accesses to NAND controller. > > 6) Removes useless bitwise OR with zeroes. > > Link to v1: > https://lore.kernel.org/linux-mtd/20230412061700.1492474-1-AVKrasnov@sberdevices.ru/ > Link to v2: > https://lore.kernel.org/linux-mtd/20230426073632.3905682-1-AVKrasnov@sberdevices.ru/ > Link to v3: > https://lore.kernel.org/linux-mtd/20230510110835.26115-1-AVKrasnov@sberdevices.ru/ > Link to v4: > https://lore.kernel.org/linux-mtd/20230515094440.3552094-1-AVKrasnov@sberdevices.ru/ > > Changelog: > > v1 -> v2: > * Add patch which renames dts value for chip select. > * Add patch which moves OOB to non-protected ECC area. > v2 -> v3: > * Change patch which fixes read/write access according discussion link > in 1) above. > v3 -> v4: > * Remove patch which renames dts value for chip select. > Here is link to discussion: > https://lore.kernel.org/linux-mtd/20230510110835.26115-7-AVKrasnov@sberdevices.ru/ > * Pass 1 to 'meson_nfc_queue_rb()' in case of NAND_OP_WAITRDY_INSTR. > This fixes ONFI page processing during NAND driver initialization. > v4 -> v5: > * Move update of 'NFC_CMD_RB_INT' to the separate patch. > * Replace code which uses extra status and READ0 commands for waiting > command with 'nand_soft_waitrdy()'. In fact this patch adds second > mode for command waiting by using 'nand_soft_waitrdy()'. > * For OOB layout patch see changelog in a patch file. > * For check length patch see changelog in a patch file. > > Arseniy Krasnov (6): > mtd: rawnand: meson: fix ready/busy command > mtd: rawnand: meson: wait for command in polling mode > mtd: rawnand: meson: only expose unprotected user OOB bytes > mtd: rawnand: meson: use macro for OOB area > mtd: rawnand: meson: check buffer length > mtd: rawnand: meson: remove unneeded bitwise OR with zeroes > > drivers/mtd/nand/raw/meson_nand.c | 234 +++++++++++++++++++++++------- > 1 file changed, 182 insertions(+), 52 deletions(-) >
Thanks, Miquèl
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